first on HVec

[Mark Feeney]

Hi all,

core.typed 0.3.11

user=> (t/cf (t/let [x :- (t/Option '[t/Num String]) nil] (first x)))

(t/Option (t/U String Number))

I'd expect (t/Option t/Num) here.  Is the String really valid somehow?

Thanks,

Mark

[Ambrose Bonnaire-Sergeant]

This is core.typed being overly conservative. I'd guess the HVec special case

in the implementation of checking `first` does not handle unions very well.

Patch welcome/please submit an issue.

Thanks,

Ambrose

[Mark Feeney]

Created http://dev.clojure.org/jira/browse/CTYP-276

Could you please point me to the code you're thinking of?  I'm not that confident I'll be able to figure out a fix, but you never know.